In the prior art, a large-area, cone shaped structure has been used to support the pixel above the readout integrated circuit and to also provide electrical interconnect between the pixel and the integrated circuit.
The performance of microbolometer pixels may be degraded by parts of the pixel structure that are necessary but do not contribute to the image signal. One example of this is the pixel contact structure that both physically supports the pixel and provides electrical interconnect from the suspended pixel to the integrated circuit over which the pixel is suspended. Historically, the pixel contact structure is formed as a large, sloped, cone-shaped structure which takes significant area away from the active sensing portion of the pixel. This is especially significant as pixel sizes are reduced.
The prior art method and structure results in a large fraction of the pixel area being used to support the pixel. This support area may not provide a signal and thus may be considered wasted space in the pixel. This large area also may not scale well, and the contact structure represents an even larger fraction of the pixel area as the pixel size is reduced.
A need, therefore, exists for a way to improve microbolometer pixel structure to enhance performance.